Conventional animal totes are constructed of cardboard and provided with air passages that ventilate the interior of the container to permit the animals to breath. To prevent contaminated air from entering the container, the air passages are covered with a filter material. Since small animals, such as laboratory rats, are capable of gnawing or chewing through a variety of materials, the filter material cannot be directly exposed to the interior of the container, otherwise the animals might eat the filter material, thereby destroying the contamination prevention that the filter material provides.
It is important in the transportation of certain animals to minimize the risk of contamination of the interior of the container with unfiltered air.
To cover the air passages with filter material in the conventional type of cardboard container constructions, first a sheet of wire mesh is placed across the opening of the container. Then, a layer of filter material, such as a woven or spun filter material, is placed over the mesh to cover the opening. This results in a construction wherein the animal contained within the tote is required to chew through the wire mesh before it can reach the filter material. Since wire mesh is difficult to chew through, the filter materials remains intact so that adequate contamination prevention is provided.
In the conventional construction, however, the application of the wire mesh and filter layers across the openings of the container is required to be performed manually, thereby increasing the amount of manual labor required to assemble the containers. To decrease the assembly time, the wire mesh and filter layers are frequently fastened to the exterior of the container by using staples or similar fasteners. Although this increases the efficiency of container assembly, it makes it difficult to change the filter material when the container is reused. Further, since the overall construction of the container is of a cardboard like material, the container can only be reused a limited number of times and then must be discarded.